A variety of conventional internal combustion engines (“ICE”) known in the art, in spite of almost 150 years of development, still suffer from low efficiency, high levels of harmful exhausts, and load-dependent performance, among other shortcomings. The efficiency of heat engines is generally low due, at least in part, to theoretical thermodynamic limitations of ideal cycles, as well as additional energy losses due to deviations from ideal cycles and friction between moving parts. Typically, only up to about 30% of the chemical energy of the fuel is converted into useful work. About 40% is removed as heat by cooling water, while the remaining 30% is lost with exhaust gases.
In addition, various gases, harmful for the environment and humans, such as unburned fuel, NOx and others are formed as a byproduct of engine operation, mainly due to a very limited ability to control the combustion process. Further, the efficiency of heat engines is optimized for a narrow range of power loads. In reality, these engines seldom operate in these optimal ranges, thus operating efficiency is reduced.
The LPPE engine, disclosed in international application No. PCT/US03/05749 filed on Feb. 26, 2003 (International Publication Number WO 03/074840), incorporated herein by reference, while having a number of important advantages, may have few disadvantages, such as large amount of water that has to be pushed during each cycle and need for computer control.